NanoDrop UV-Vis spectrophotometers
Posted 28 June 2013 - 02:34 AM
has anyone used NanoDrop UV-Vis spectrophotometers for protein Concentration determination ?
how is the performance of this instrument ??
(have heard that this show lot of variation in measurment )
Posted 28 June 2013 - 04:22 AM
also, many have found that you should use 2ul, rather than 1 or 1.5ul, for consistent and reproducible readings (regardless of method).
talent does what it can
genius does what it must
i used to do what i got paid to do
Posted 28 June 2013 - 05:12 AM
Posted 07 July 2013 - 03:30 PM
However, I have found them to be inconsistent when measuring low concentration samples (OD for 1cm pathlength < 0.3).
Edited by labtastic, 07 July 2013 - 03:31 PM.
Posted 07 July 2013 - 05:14 PM
Absorption of radiation in the near UV by proteins depends on the Tyr and Trp content (and to a very small extent on the amount of Phe and disulfide bonds). Therefore the A 280 varies greatly between different proteins; for a 1 mg/mL solution, from 0 up to 4 for some tyrosine-rich wool proteins, although most values are in the range 0.5-1.5 (Kirschenbaum, D. M. (1975) Molar absorptivity and A1%/1 cm values for proteins at selected wavelengths of the ultraviolet and visible regions. Anal. Biochem. 68, 465-484).The advantages of this method are that it is simple, and the sample is recoverable.
Posted 08 July 2013 - 05:33 AM
I also use 2ul per reading to eliminate some of the error that can come from technique.
Posted 12 July 2013 - 10:44 AM